I. Field of the Invention
This invention relates to a semiconductor integrated circuit with high operating speed, and more particularly to a semiconductor integrated circuit wherein the operating speed is not influenced by temperature.
II. Description of the Prior Art
Generally, the current through an IGFET, such as a metal oxide semiconductor (MOS) transistor, decreases with increased temperature due to the lowering of the mobility of the minority carriers (electrons or holes). Accordingly, the response time in conventional MOS integrated circuits increases with temperature. For instance, the response time at 85.degree. C. is 400 n.sec., as compared to 300 n.sec. at 25.degree. C. due to the fact that as the current through an MOS transistor decreases with temperature, the charge-discharge current at some circuit points decreases and more time is required to charge and discharge it. Accordingly, the operating speed of a conventional device is influenced by temperature as shown in FIG. 1. The solid line and dotted line show response time and current through an MOS transistor, respectively.